Simple and PowerfulRated 5 out of 5 stars

If you're making a website or an Add-on, you're going to need this extension. The detailed selections on what errors pop up, the grouping of errors, the domain blocker, and the search are all regularly used in any web development project. I don't know what add-ons would be like if the developers didn't have this tool at their disposal. I know it's helped my add-ons as much as the DOM Inspector, if not more.